<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        input::-webkit-input-placeholder{  color:red; font-size:14px; }
        input:-moz-placeholder{  color:red; font-size:14px;}
        input::-moz-placeholder{  color:red;font-size:14px; }
        input:-ms-input-placeholder{  color:red; font-size:14px; }
        input{
            height:50px;
        }
    </style>
</head>
<body>
<input type="text" placeholder="张三">
</body>
</html>